Hello again fellow mechanics and apprentices! This time around, I’d like to share some experiences with hub seals and brake jobs. Particularly an old Freightliner.
The other day, we had a big, white, ugly Freightliner come into the shop for a PTO install and a 90 day inspection. During the inspection, a fellow mechanic found the rear axle brakes and front left drive axle brakes were below our minimum thickness, 3/8 of an inch, and splitting. This is all well and good. Most of the time, a brake job takes about half an hour to 45 minutes. Notice I say MOST of the time. On this particular unit, with 1.2 million kms on it, the story was completely different. For starters, the rear axle had two completely different slack adjusters on it. One side had your standard run of the mill slack adjuster while the other side had an ugly, big Gunnite slack adjuster. For those who are unfamiliar with Gunnite slacks, they are the style that look like they have a piston, and it takes 8 arms to adjust them. You’ll know what they are when you need to bend your arms at unnatural angles to do anything. Back to the point. For any brake job, the drums need to come off. Before that can happen, the wheels need to come off. Well, in order to get the wheels off, the fenders had to come off because the air bags where too small and the tires would hit the inside of the fender walls. As soon as the drum came off, it was very obvious the wheel seal was leaking. Not weeping, not slightly damp, full on leaking. But that’s for later.
On drum brakes, there is a spider, a plate which holds your S-cam, your anchor pins, and the bushings which hold the pins and allow some movement of the pins. This spider was so bunged up that the bushings were seized in the spider, and the pins were seized in the bushings. How seized you might ask? It took a 4 pound sledge and a bushing splitter to get them out. My bushing splitter is a tiny little thing on a tiny little Hyundai air hammer. Essentially nothing more than a little pop gun on an air hose. You get it. Needless to say it was not a fun job. It took all day to get these brakes changed. That’s one side. Thankfully my companion was able to get the other two sets changed out.
On that note, we both determined that the last person to work on these brakes was not thinking about the next guy to fix these brakes. No anti-seize was used, the spiders were bent out of shape, and the bushings were pounded into the spiders, making the pins seize in them. The point is that if you don’t want to be tracked down and and beaten with a 6-foot pipe wrench, please, for the love of god and all things sane, please remember to consider the next guy in line, and make sure that you do your best to keep it as easy as possible for them!